Antinociceptive Activity of Flavonoid-Rich Ethylacetate Fraction of Ocimum gratissimum L. Leaves in Mice doi.org/10.26538/tjnpr/v5i6.18

Abstract

Ocimum gratissimum L. in an economic plant of immense ethnomedicinal properties. This study evaluated the anti-nociceptive activity of the sequential extracts and flavonoid-rich ethylacetate fraction of O. gratissimum (EAFOg) in mice. The sequential extracts of the dried leaves in hexane, chloroform and methanol and the ethylacetate fraction were assessed in acetic acid-induced writhing and formalin test in mice. Further antinociceptive activity of the ethylacetate  fraction (25, 50 and 100 mg/kg) was investigated in hot plate, acetic acid and formalin tests. The results revealed that antinociceptive activity was in the order of ethylacetate > methanol > chloroform > hexane. EAFOg demonstrated activity in the hot plate, acetic acid and formalin test, respectively. The antinociceptive activity of EAFOg (100 mg/kg) was not reversed by pre-treatment with the opioid antagonist (Naloxone, 1 mg/kg, i.p) when assessed in the hot plate test. Furthermore, the antinociceptive effect of EAFOg (100 mg/kg) was reversed by L-NAME (10mg/kg) and yohimbine (2 mg/kg) but not atropine (2 mg/kg) when assessed in the acetic acid-induced writhing test. This suggests an interaction with the nitric oxide and adrenergic pathway. The results suggest that the flavonoid-rich ethylacetate fraction of O. gratissimum (EAFOg) may have beneficial effect against neurogenic and inflammatory pain.